With an introduction by Albert Einstein: The collected letters of the Renaissance astronomer who discovered the laws of planetary motion. Astronomer and mathematician Johannes Kepler made major contributions to the Scientific Revolution of the seventeenth century. While his achievements are well-documented elsewhere, this volume of his personal correspondence offers a rare window into the life of a man who pursued knowledge through a dangerous and turbulent period of history. Spanning more than thirty years, from 1596 to the end of his life, Kepler's letters reveal the internal conflicts of a devout Protestant who nevertheless opposed many pronouncements of the Church, an eminent man of science who was also swayed by astrology, and a contemporary of Galileo who served three succeeding Holy Roman Emperors.